M3.9 Earthquake 135 km SSE of False Pass, Alaska — November 20, 2024
2024-11-20 18:00:58 UTC (2024-11-20) · approx. 7:00 AM UTC-11 local
On November 20, 2024 at 18:00 UTC, a magnitude 3.9 shallow crustal earthquake struck 135 km SSE of False Pass, Alaska, at a depth of 20.9 km and coordinates 53.6808°, -162.8835°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.2 mainshock that occurred 21 days ago 106 km SSE of False Pass, Alaska. Since the mainshock, the USGS has recorded 19 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
-162.8835°E
Technical Information
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Common Questions
How strong was the magnitude 3.9 earthquake near False Pass, Alaska?
The magnitude 3.9 earthquake that struck 135 km SSE of False Pass, Alaska on November 20, 2024 at 18:00 UTC had a depth of 20.9 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.2 one earlier?
No. This magnitude 3.9 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 106 km SSE of False Pass, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us7000nw62). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2024, November 20, 2024). M3.9 Earthquake 135 km SSE of False Pass, Alaska — November 20, 2024. Retrieved January 30, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000nw62/